Research project: Birkin: Hydrodynamic Modulated Voltammetry (HMV)

Hydrodynamic devices use convection to enhance the rate of mass transport to the electrode and can offer advantages over techniques which operate in stagnant solution. We have developed a novel oscillating jet system (see figure) which is employed to produce modulated hydrodynamic flow around an electrode. The oscillating jet is constructed from a funnel and membrane and has a number of advantages. First, the electrode is stationary and avoids the mechanical issues associated with electrode vibration. Second, a small amplitude oscillation of membrane gives rise to a larger fluid motion in the exit tube of the funnel. This technique is employed to study catalytically important nanostructured surfaces. These electrodes have a high roughness factor which exhibits significant high double layer charging and other surface dependant currents. These surface components can cause considerable difficulty in interpretation of the results from an experiment investigating of a solution phase species. However, these contributions are removed by using a HMV system. The detection limit of such a system is under investigation along with electrochemical and high-speed imaging studies of the novel apparatus developed at Southampton.